The defer statement in Swift is used to execute a set of statements just before the code block in which it appears exits. It is typically used to perform clean-up or other tasks that should be done regardless of how the code block exits.
For example, if you need to close a file after it has been opened, you can use a defer statement to ensure that the file is always closed regardless of how the code block exits:
let file = openFile(“example.txt”)
defer {
closeFile(file)
}
// Do something with the file…